libkmod/libkmod-file.c

   1 /*
   2  * libkmod - interface to kernel module operations
   3  *
   4  * Copyright (C) 2011-2013  ProFUSION embedded systems
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  19  */
  20
  21 #include <stdbool.h>
  22 #include <stdio.h>
  23 #include <stdlib.h>
  24 #include <errno.h>
  25 #include <string.h>
  26 #include <sys/types.h>
  27 #include <sys/stat.h>
  28 #include <sys/mman.h>
  29 #include <unistd.h>
  30
  31 #include "libkmod.h"
  32 #include "libkmod-private.h"
  33
  34 #ifdef ENABLE_XZ
  35 #include <lzma.h>
  36 #endif
  37 #ifdef ENABLE_ZLIB
  38 #include <zlib.h>
  39 #endif
  40
  41 struct kmod_file;
  42 struct file_ops {
  43         int (*load)(struct kmod_file *file);
  44         void (*unload)(struct kmod_file *file);
  45 };
  46
  47 struct kmod_file {
  48 #ifdef ENABLE_XZ
  49         bool xz_used;
  50 #endif
  51 #ifdef ENABLE_ZLIB
  52         gzFile gzf;
  53 #endif
  54         int fd;
  55         bool direct;
  56         off_t size;
  57         void *memory;
  58         const struct file_ops *ops;
  59         const struct kmod_ctx *ctx;
  60         struct kmod_elf *elf;
  61 };
  62
  63 #ifdef ENABLE_XZ
  64 static void xz_uncompress_belch(struct kmod_file *file, lzma_ret ret)
  65 {
  66         switch (ret) {
  67         case LZMA_MEM_ERROR:
  68                 ERR(file->ctx, "xz: %s\n", strerror(ENOMEM));
  69                 break;
  70         case LZMA_FORMAT_ERROR:
  71                 ERR(file->ctx, "xz: File format not recognized\n");
  72                 break;
  73         case LZMA_OPTIONS_ERROR:
  74                 ERR(file->ctx, "xz: Unsupported compression options\n");
  75                 break;
  76         case LZMA_DATA_ERROR:
  77                 ERR(file->ctx, "xz: File is corrupt\n");
  78                 break;
  79         case LZMA_BUF_ERROR:
  80                 ERR(file->ctx, "xz: Unexpected end of input\n");
  81                 break;
  82         default:
  83                 ERR(file->ctx, "xz: Internal error (bug)\n");
  84                 break;
  85         }
  86 }
  87
  88 static int xz_uncompress(lzma_stream *strm, struct kmod_file *file)
  89 {
  90         uint8_t in_buf[BUFSIZ], out_buf[BUFSIZ];
  91         lzma_action action = LZMA_RUN;
  92         lzma_ret ret;
  93         void *p = NULL;
  94         size_t total = 0;
  95
  96         strm->avail_in  = 0;
  97         strm->next_out  = out_buf;
  98         strm->avail_out = sizeof(out_buf);
  99
 100         while (true) {
 101                 if (strm->avail_in == 0) {
 102                         ssize_t rdret = read(file->fd, in_buf, sizeof(in_buf));
 103                         if (rdret < 0) {
 104                                 ret = -errno;
 105                                 goto out;
 106                         }
 107                         strm->next_in  = in_buf;
 108                         strm->avail_in = rdret;
 109                         if (rdret == 0)
 110                                 action = LZMA_FINISH;
 111                 }
 112                 ret = lzma_code(strm, action);
 113                 if (strm->avail_out == 0 || ret != LZMA_OK) {
 114                         size_t write_size = BUFSIZ - strm->avail_out;
 115                         char *tmp = realloc(p, total + write_size);
 116                         if (tmp == NULL) {
 117                                 ret = -errno;
 118                                 goto out;
 119                         }
 120                         memcpy(tmp + total, out_buf, write_size);
 121                         total += write_size;
 122                         p = tmp;
 123                         strm->next_out = out_buf;
 124                         strm->avail_out = BUFSIZ;
 125                 }
 126                 if (ret == LZMA_STREAM_END)
 127                         break;
 128                 if (ret != LZMA_OK) {
 129                         xz_uncompress_belch(file, ret);
 130                         ret = -EINVAL;
 131                         goto out;
 132                 }
 133         }
 134         file->xz_used = true;
 135         file->memory = p;
 136         file->size = total;
 137         return 0;
 138  out:
 139         free(p);
 140         return ret;
 141 }
 142
 143 static int load_xz(struct kmod_file *file)
 144 {
 145         lzma_stream strm = LZMA_STREAM_INIT;
 146         lzma_ret lzret;
 147         int ret;
 148
 149         lzret = lzma_stream_decoder(&strm, UINT64_MAX, LZMA_CONCATENATED);
 150         if (lzret == LZMA_MEM_ERROR) {
 151                 ERR(file->ctx, "xz: %s\n", strerror(ENOMEM));
 152                 return -ENOMEM;
 153         } else if (lzret != LZMA_OK) {
 154                 ERR(file->ctx, "xz: Internal error (bug)\n");
 155                 return -EINVAL;
 156         }
 157         ret = xz_uncompress(&strm, file);
 158         lzma_end(&strm);
 159         return ret;
 160 }
 161
 162 static void unload_xz(struct kmod_file *file)
 163 {
 164         if (!file->xz_used)
 165                 return;
 166         free(file->memory);
 167 }
 168
 169 static const char magic_xz[] = {0xfd, '7', 'z', 'X', 'Z', 0};
 170 #endif
 171
 172 #ifdef ENABLE_ZLIB
 173 #define READ_STEP (4 * 1024 * 1024)
 174 static int load_zlib(struct kmod_file *file)
 175 {
 176         int err = 0;
 177         off_t did = 0, total = 0;
 178         unsigned char *p = NULL;
 179
 180         errno = 0;
 181         file->gzf = gzdopen(file->fd, "rb");
 182         if (file->gzf == NULL) {
 183                 return -errno;
 184         }
 185         file->fd = -1; /* now owned by gzf due gzdopen() */
 186
 187         for (;;) {
 188                 int r;
 189
 190                 if (did == total) {
 191                         void *tmp = realloc(p, total + READ_STEP);
 192                         if (tmp == NULL) {
 193                                 err = -errno;
 194                                 goto error;
 195                         }
 196                         total += READ_STEP;
 197                         p = tmp;
 198                 }
 199
 200                 r = gzread(file->gzf, p + did, total - did);
 201                 if (r == 0)
 202                         break;
 203                 else if (r < 0) {
 204                         int gzerr;
 205                         const char *gz_errmsg = gzerror(file->gzf, &gzerr);
 206
 207                         ERR(file->ctx, "gzip: %s\n", gz_errmsg);
 208
 209                         /* gzip might not set errno here */
 210                         err = gzerr == Z_ERRNO ? -errno : -EINVAL;
 211                         goto error;
 212                 }
 213                 did += r;
 214         }
 215
 216         file->memory = p;
 217         file->size = did;
 218         return 0;
 219 error:
 220         free(p);
 221         gzclose(file->gzf);
 222         return err;
 223 }
 224
 225 static void unload_zlib(struct kmod_file *file)
 226 {
 227         if (file->gzf == NULL)
 228                 return;
 229         free(file->memory);
 230         gzclose(file->gzf); /* closes file->fd */
 231 }
 232
 233 static const char magic_zlib[] = {0x1f, 0x8b};
 234 #endif
 235
 236 static const struct comp_type {
 237         size_t magic_size;
 238         const char *magic_bytes;
 239         const struct file_ops ops;
 240 } comp_types[] = {
 241 #ifdef ENABLE_XZ
 242         {sizeof(magic_xz), magic_xz, {load_xz, unload_xz}},
 243 #endif
 244 #ifdef ENABLE_ZLIB
 245         {sizeof(magic_zlib), magic_zlib, {load_zlib, unload_zlib}},
 246 #endif
 247         {0, NULL, {NULL, NULL}}
 248 };
 249
 250 static int load_reg(struct kmod_file *file)
 251 {
 252         struct stat st;
 253
 254         if (fstat(file->fd, &st) < 0)
 255                 return -errno;
 256
 257         file->size = st.st_size;
 258         file->memory = mmap(0, file->size, PROT_READ, MAP_PRIVATE, file->fd, 0);
 259         if (file->memory == MAP_FAILED)
 260                 return -errno;
 261         file->direct = true;
 262         return 0;
 263 }
 264
 265 static void unload_reg(struct kmod_file *file)
 266 {
 267         munmap(file->memory, file->size);
 268 }
 269
 270 static const struct file_ops reg_ops = {
 271         load_reg, unload_reg
 272 };
 273
 274 struct kmod_elf *kmod_file_get_elf(struct kmod_file *file)
 275 {
 276         if (file->elf)
 277                 return file->elf;
 278
 279         file->elf = kmod_elf_new(file->memory, file->size);
 280         return file->elf;
 281 }
 282
 283 struct kmod_file *kmod_file_open(const struct kmod_ctx *ctx,
 284                                                 const char *filename)
 285 {
 286         struct kmod_file *file = calloc(1, sizeof(struct kmod_file));
 287         const struct comp_type *itr;
 288         size_t magic_size_max = 0;
 289         int err;
 290
 291         if (file == NULL)
 292                 return NULL;
 293
 294         file->fd = open(filename, O_RDONLY|O_CLOEXEC);
 295         if (file->fd < 0) {
 296                 err = -errno;
 297                 goto error;
 298         }
 299
 300         for (itr = comp_types; itr->ops.load != NULL; itr++) {
 301                 if (magic_size_max < itr->magic_size)
 302                         magic_size_max = itr->magic_size;
 303         }
 304
 305         file->direct = false;
 306         if (magic_size_max > 0) {
 307                 char *buf = alloca(magic_size_max + 1);
 308                 ssize_t sz;
 309
 310                 if (buf == NULL) {
 311                         err = -errno;
 312                         goto error;
 313                 }
 314                 sz = read_str_safe(file->fd, buf, magic_size_max + 1);
 315                 lseek(file->fd, 0, SEEK_SET);
 316                 if (sz != (ssize_t)magic_size_max) {
 317                         if (sz < 0)
 318                                 err = sz;
 319                         else
 320                                 err = -EINVAL;
 321                         goto error;
 322                 }
 323
 324                 for (itr = comp_types; itr->ops.load != NULL; itr++) {
 325                         if (memcmp(buf, itr->magic_bytes, itr->magic_size) == 0)
 326                                 break;
 327                 }
 328                 if (itr->ops.load != NULL)
 329                         file->ops = &itr->ops;
 330         }
 331
 332         if (file->ops == NULL)
 333                 file->ops = &reg_ops;
 334
 335         err = file->ops->load(file);
 336         file->ctx = ctx;
 337 error:
 338         if (err < 0) {
 339                 if (file->fd >= 0)
 340                         close(file->fd);
 341                 free(file);
 342                 errno = -err;
 343                 return NULL;
 344         }
 345
 346         return file;
 347 }
 348
 349 void *kmod_file_get_contents(const struct kmod_file *file)
 350 {
 351         return file->memory;
 352 }
 353
 354 off_t kmod_file_get_size(const struct kmod_file *file)
 355 {
 356         return file->size;
 357 }
 358
 359 bool kmod_file_get_direct(const struct kmod_file *file)
 360 {
 361         return file->direct;
 362 }
 363
 364 int kmod_file_get_fd(const struct kmod_file *file)
 365 {
 366         return file->fd;
 367 }
 368
 369 void kmod_file_unref(struct kmod_file *file)
 370 {
 371         if (file->elf)
 372                 kmod_elf_unref(file->elf);
 373
 374         file->ops->unload(file);
 375         if (file->fd >= 0)
 376                 close(file->fd);
 377         free(file);
 378 }